Process Mineralogy Study on an Iron Ore Deposit Associated with Gallium and Germanium in Fujian Province, China

Multiple technics including microscope, X-ray diffraction (XRD), SEM energy dispersive spectrometer, electron probe micro-analyzer (EPMA) and mineral liberation analyser (MLA) were adopted to study the mineral compositions, dissemination characteristics and occurrences of gallium and germanium-bearing minerals in a sedimentary hydrothermal iron ore associated with gallium and germanium in Fujian Province, China. The substitution mechanisms of gallium and germanium are also discussed. The results show that the main valuable metal in the ores is iron, accompanied by the valuable metal elements of gallium, germanium, molybdenum and silver. Magnetite is the predominant iron mineral and the most important gallium and germanium-bearing phase. Gallium and germanium enter the lattice of carrier minerals mainly in the form of isomorphism replacement and show diverse occurrences. Most magnetite in the ores is embedded in gangue minerals, with extremely uneven distribution of grain size. The grain size mostly ranges from 0.005 to 0.32 mm, and the proportion of grain size less than 0.01 mm is as high as 16.26%, resulting the grinding and dissociation difficult. The method of magnetic separation can be used to recover magnetite firstly, followed by hydrometallurgical means of acid leaching, purification and extraction to recover iron, gallium and germanium from magnetite concentrate. The theoretical grades and recovery rates of gallium and germanium of the ore are 27×10^-6, 40% and 112×10^-6, 82%, respectively.